Five years of experience with fine structure stimulation strategies

摘要

An evaluation of a fine structure stimulation strategy based on "Channel Specific Sampling Sequences" (CSSS) is presented. In acute comparisons, speech perception with CSSS is on a par with a standard CIS setting. Switching from CIS to CSSS in many cases causes a subjective pitch shift towards lower frequencies. Measurements with harmonic tone complexes with a spectral roll-off of 9 dB/octave revealed a pitch range expansion of up to 5 semitones at the low-frequency end. Electric-acoustic pitch matching experiments with single-sided deaf subjects indicate that for low pitch perception a sufficiently deep inserted stimulation electrode represents a necessary condition. With stimulation electrode positions in the medial or basal regions of the cochlea, it is not possible to elicit low pitch percepts, independent of rate cues represented in the stimulation patterns.